This is probably really obvious to a lot of people...but how do I view the monster traits/abilities?

Like if I hover over the Zombie, it says Undead and Bloodless. I dont know where to figure out what these traits mean. If I move my mouse away from the Zombie, the monster info disappears obviously. If I right click the monster, its traits are hidden by attack commands.

You can view traits via the codex - click the menu button in the top right corner of the game screen and then click the Enemy Statuses tab (the second last one) for a description of all the traits you've seen on enemies so far.

You can also view monster traits the same way as you'd examine your own traits when you right click an enemy: Their traits aren't obscured by attack commands, the traits move to become icons on the enemy's portrait, which can be hovered over individually.